The dramatic increase in the number of Tasers across London from 800 to 6,500 is deeply concerning (Met spends £800,000 a year on Taser rollout for response cars, 18 January). As we've seen in other parts of the UK and frequently in the US, these dangerous and potentially lethal weapons are more likely to be misused if more officers are armed with them. Tasers should only be used where there's a serious risk to life or of very serious injury and only by officers who are trained to the rigorous, exacting standards of firearms officers.Tom FyansAmnesty International UK

• Lance Armstrong successfully sued the Sunday Times for libel when they claimed he cheated (Report, 18 January). I'd like to see him charged with perjury – if only so we could really see just how equal the US extradition treaty is.Philip CunninghamLondon

• It would be difficult to explain what is the difference between the subcontracting work by Serco, on behalf of the National Health Service, and the technician, who has now been sacked for subcontracting his work to a Chinese computer programmer (Bob the outsourcer, 18 January). Presumably the latter will now understand that he should have set up his own subcontracting programming company to do the work, or used Serco.Leo MercierZelah, Cornwall

• A northbound Piccadilly line train, packed tight with commuters, drew into a station (Letters, 18 January). A passenger was heard to enquire "Is this Cockfosters?". The inevitable response was: "No, my name's Smythe." First heard during a tea-break in 1961 but surely much older than that.Tom CoultateLeighton Buzzard, Bedfordshire

• If the journey compares with crossing Anglesey from Holyhead then getting off at Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiligogogoch may take a dangerously long time to achieve.Wyn ThomasSwansea